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Discussion Starter · #1 ·
I'm hoping someone here might know what the problem is with the my fan cooled Pro X.I'm having a hell of a time getting this thing dialed in and running right.Some of you "fanatics" that have been around here awhile may remember all the problems I had with this machine last year.I've come to find out that it's not just my sled, but many of the 2002 Pro X fans.I talked to my dealer today and they said they have two of them that customers brought back because they don't run once warmed up.(I've already been there and got that straightened out)[xx(]Well at least mine runs.I've dropped three jet sizes and backed out the pilot screws 1+1/4 turns and the machine still wants to load up on the bottom end.There is also a dead spot right at 5200 rpm.I'm no master mechanic sled tuning guru, but I suspect that this model sled may have some serious tunability issues.
Is there anyone here that works for Polaris that might know whats going on here?I would like to contact the company to see if they have any service bulletins out for this machine, but I can't seem to find a way to contact them.It seems to me that Polaris should step up and take action if they have a batch of bad sleds out there that people like my put there hard earned money down to buy.
If anyone has any advice on what I should do, I'm all ears.The sled runs, it has 690 miles on it, but it really sucks to have to worry about it-especially now that my girlfreind is the primary pilot.PLEASE, any helpful advice would be, well..., helpful.[;)]
 

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Well, I'll do that best I can with what I know...

The dead spot at 5200 rpm, does it seem like too much gas or not enough? If too much, lower your carb needles (raise the c-clip) one notch to see if that helps. If not enough gas, raise the carb needles (drop the c-clip) one notch. That should take care of the midrange for you.

For the bottom end, slowly turn the pilot air screws (an equal amount on both carbs) until the sled idles at its highest rpm. If you wind up with more than three turns out from lightly seated to get it right then you need to go down one size in your pilot jets (like from a 40 to a 35). Then, start over with the pilot air screw adjustment.

Hope that helps...
 

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Discussion Starter · #3 ·
I'm not sure if she's off in the midrange, I havn't read the plugs since the last ride.It seems like the needle adjustment would effect a slightly wider range between 3/8 & 3/4 throttle.When I say it has a dead spot at 5200 rpm, I mean it seems just fine at 5100& 5300.It almost sounds like it skips or runs on one cylinder, but only at exactly 5200 rpm.It's weird.I'll read the plugs and see how they're coloring and change the needle position if necessary.I should have threaded the pilot screws all the way in to see where they were set initially, I didn't dare back them out any more because I don't want them holding in there by two threads or something.No more than 3 turns from seated, eh?Thanks alot for your input.Here's some more info on how it's set up now:
carb-Mikuni VM34AL
[email protected] ft
main jets-290&280
needle clip-#3position
pilot jet-40
air screw-3/4 turn from factory(so the set up sheet says), so now 2 turns out
I'll probobly mess around with it more tomarrow, but keep your ideas coming.Thanks again for your input ACMan.
 

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maybe, just maybe polaris offers an aftermarket needle. I've had an experience like yours, but with a moto-x bike. On select models/years there would be a dead spot that you just couldn't do away with by changing the carb settings no matter what. The special needles (from the factory or aftermarket) have muli tapers and/or flat spots on them to get rid of that lull. I'm not fimilar with this pro-x tuning issue but that could be one possibility to look into....just a thought
 

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Discussion Starter · #5 ·
I got my issue of SnowGoer today and some poor sucker wrote them a letter about having problems with his Pro X fan.I thought that was kind of funny.
Well, anyway, I picked up some pilot jets today but I didn't have time to work on it yet.i'm sure I'll get it dialed in sometime.......
The reply to that letter in SnowGoer said that polaris had a service bulletin out with a revised jetting chart and recomended changing the timing.I asked my dealer today and they didn't know anything about it.They were actually working on one when I was there.There must be some kind of communication breakdown between Minn & Ny.
Oh, yeah, they do have different needles for it-I think that might help the 5200 rpm stutter.thanks for the tip.
 

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Discussion Starter · #6 ·
OH MY GOD I GOT IT!!!I actuall enjoyed a day of flawless running with my Pro x fan!The timing was off and thats why it wouldn't run right no matter what I did with the jetting.The timing change made that misereble mid range studder disappear.I got alot warmer so I jetted down one more size and it acts like it's gonna run great
 
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